The present invention concerns an electronic wristwatch including a flexible wristband having a body made of moulded elastomer, an electronic watch movement including components mounted on a flexible printed circuit film, said components and said flexible film being incorporated in the body of the wristband by overmoulding of the elastomer of said body, a display unit controlled by the watch movement, and an electric power source connected to the watch movement. The invention also concerns a method for manufacturing such a wristwatch.
French Patent Application No. 2 595 480 provides a wristwatch of this type, including a liquid crystal or similar display unit, controlled by an electronic circuit powered by a battery or another electric power source. The constituent elements of the electronic circuit and the display unit itself are incorporated in the wristband, which is manufactured in a flexible plastic material or similar by overmoulding these elements in the form of a flat strip of small thickness, the display screen being located in the median part of the wristband. The battery housing is arranged in a thicker part located at one of the ends of the wristband, which can carry a fastening element for the latter. In proximity to the display screen several touch sensitive control buttons are provided which are integrated inside the wristband, but whose upper surface is flush with the corresponding surface of the wristband. Since the display screen is integrated in the wristband owing to the duplicate moulding thereof, the upper surface of the screen must be flush with the upper surface of the wristband so that the indications displayed are visible, unless the wristband is moulded in a transparent plastic material allowing the display to be read.
With such a structure, it will be understood that the plastic material used for the overmoulding has to be relatively soft for the wristband to be sufficiently flexible. Consequently, the components embedded in this material are not well protected against external pressure and are liable to become damaged quickly when the watch is worn on the wrist. This may explain the fact that this type of watch has not met with commercial success to date.
British Patent Application No. 1 574 730 discloses a wristwatch whose case and wristband are formed of a single moulded part, for example made of polypropylene, this wristband being connected to the case by thinned parts which form flexible hinges. The wristband includes housings fitted with control buttons which are electrically connected to the electronic modules mounted in the case by a printed circuit film, which is embedded in the plastic material. The manufacture of such a watch is relatively complex because it requires multiple elements to be mounted in the case and the housings provided in the wristband.
The object of the present invention is to create a wristwatch wherein most or all of the electronic components are embedded in a flexible wristband, but are nonetheless sheltered from damage which could be caused by external influences during normal use of the watch. Furthermore, this watch should be able to be manufactured at a very low cost.
The invention thus concerns an electronic wristwatch of the type indicated in the preamble, characterised in that it includes a plurality of external elements mounted on the body of the wristband and connected to each other in a flexible way by the wristband, at least certain of these external elements being cases arranged so as to cover and protect watch movement components and the display unit.
Thus, the fragile elements of the watch, namely the watch movement components and the display unit, are mounted economically in or on the wristband and are protected by sufficiently rigid cases, which may be extremely simple and inexpensive while having an attractive external appearance. The wristwatch may be completed by other external elements, for example decorative elements having a similar appearance to that of the cases and distributed along the body of the wristband.
The invention also provides an advantageous method for manufacturing such a wristwatch, including the following steps: the watch movement components are mounted on the flexible printed circuit film, which includes electric connection means for connecting it to the display unit and the power source; then the body of the wristband is made by overmoulding over the flexible film and said components, with the exception of the connection means; then the display unit and the power source are connected to said connection means and the external elements are fixed to the body of the wristband.